Occurrence of colistin-resistant hypervirulent Klebsiella variicola

作者：Lu Yang, Yu Feng, Alan McNally, Zhiyong Zong · 发表于：Journal of Antimicrobial Chemotherapy · 年份：2018 · DOI：10.1093/jac/dky301 · 被引用次数：57 · 研究领域：Antibiotic Resistance in Bacteria、Invertebrate Immune Response Mechanisms、Insect symbiosis and bacterial influences

Background: A colistin-resistant mucoid Klebsiella strain was recovered from the blood of a patient in China. Hypervirulence has been reported in Klebsiella pneumoniae, but not in other Klebsiella spp. The strain was suspected to be hypervirulent and was therefore characterized. Methods: The strain was subjected to genome sequencing using both the short-read Illumina HiSeq X10 Sequencer and the long-read MinION sequencer. Precise species identification was established using average nucleotide identity based on genome sequences. Virulence and antimicrobial resistance genes were identified using ResFinder and the bigsdb database. Conjugation experiments were performed. Virulence was assessed using wax moth (Galleria mellonella) larvae with control Klebsiella strains of low virulence and hypervirulence. Results: The strain had a 5 553 341 bp circular chromosome and a 236 355 bp large plasmid. It was identified as Klebsiella variicola. The strain had multiple virulence genes encoding mucoid phenotype regulator (rmpA and rmpA2), aerobactin (iucABCD-iutA), salmochelin (iroBCDN) and yersiniabactin (irp1-2 and ybtAEPQSTUX) on the plasmid, which was not self-transmissible. It exhibited enhanced virulence in the larvae model, suggesting that the strain was hypervirulent. It was resistant to colistin (MIC = 8 mg/L) but was susceptible to amikacin, aztreonam, cefotaxime, ceftazidime, gentamicin, imipenem, meropenem, moxifloxacin, piperacillin/tazobactam, trimethoprim/sulfamethoxazole and...